Messages in this thread | | | From | Amit Kucheria <> | Date | Thu, 13 Feb 2020 18:01:14 +0530 | Subject | Re: [Patch v8 1/7] sched/pelt: Add support to track thermal pressure |
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On Thu, Feb 13, 2020 at 5:33 PM Amit Kucheria <amit.kucheria@linaro.org> wrote: > > On Wed, Jan 15, 2020 at 1:27 AM Thara Gopinath > <thara.gopinath@linaro.org> wrote: > > > > Extrapolating on the existing framework to track rt/dl utilization using > > pelt signals, add a similar mechanism to track thermal pressure. The > > difference here from rt/dl utilization tracking is that, instead of > > tracking time spent by a cpu running a rt/dl task through util_avg, the > > average thermal pressure is tracked through load_avg. This is because > > thermal pressure signal is weighted "delta" capacity and is not > > binary(util_avg is binary). "delta capacity" here means delta between the > > actual capacity of a cpu and the decreased capacity a cpu due to a thermal > > event. > > > > In order to track average thermal pressure, a new sched_avg variable > > avg_thermal is introduced. Function update_thermal_load_avg can be called > > to do the periodic bookkeeping (accumulate, decay and average) of the > > thermal pressure. > > > > Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org> > > Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> > > --- > > > > v6->v7: > > - Added CONFIG_HAVE_SCHED_THERMAL_PRESSURE to stub out > > update_thermal_load_avg in unsupported architectures as per > > review comments from Peter, Dietmar and Quentin. > > - Updated comment for update_thermal_load_avg as per review > > comments from Peter and Dietmar. > > v7->v8: > > - Fixed typo in defining update_thermal_load_avg which was > > causing build errors (reported by kbuild test report) > > > > include/trace/events/sched.h | 4 ++++ > > init/Kconfig | 4 ++++ > > kernel/sched/pelt.c | 31 +++++++++++++++++++++++++++++++ > > kernel/sched/pelt.h | 16 ++++++++++++++++ > > kernel/sched/sched.h | 1 + > > 5 files changed, 56 insertions(+) > > > > diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h > > index 420e80e..a8fb667 100644 > > --- a/include/trace/events/sched.h > > +++ b/include/trace/events/sched.h > > @@ -613,6 +613,10 @@ DECLARE_TRACE(pelt_dl_tp, > > TP_PROTO(struct rq *rq), > > TP_ARGS(rq)); > > > > +DECLARE_TRACE(pelt_thermal_tp, > > + TP_PROTO(struct rq *rq), > > + TP_ARGS(rq)); > > + > > DECLARE_TRACE(pelt_irq_tp, > > TP_PROTO(struct rq *rq), > > TP_ARGS(rq)); > > diff --git a/init/Kconfig b/init/Kconfig > > index f6a4a91..c16ea88 100644 > > --- a/init/Kconfig > > +++ b/init/Kconfig > > @@ -450,6 +450,10 @@ config HAVE_SCHED_AVG_IRQ > > depends on IRQ_TIME_ACCOUNTING || PARAVIRT_TIME_ACCOUNTING > > depends on SMP > > > > +config HAVE_SCHED_THERMAL_PRESSURE > > + bool "Enable periodic averaging of thermal pressure" > > + depends on SMP > > + > > config BSD_PROCESS_ACCT > > bool "BSD Process Accounting" > > depends on MULTIUSER > > diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c > > index bd006b7..5d1fbf0 100644 > > --- a/kernel/sched/pelt.c > > +++ b/kernel/sched/pelt.c > > @@ -367,6 +367,37 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running) > > return 0; > > } > > > > +#ifdef CONFIG_HAVE_SCHED_THERMAL_PRESSURE > > +/* > > + * thermal: > > + * > > + * load_sum = \Sum se->avg.load_sum but se->avg.load_sum is not tracked > > + * > > + * util_avg and runnable_load_avg are not supported and meaningless. > > + * > > + * Unlike rt/dl utilization tracking that track time spent by a cpu > > + * running a rt/dl task through util_avg, the average thermal pressure is > > + * tracked through load_avg. This is because thermal pressure signal is > > + * weighted "delta" capacity and is not binary(util_avg is binary). "delta > > May I suggest a slight rewording here and in the commit description, > > This is because the thermal pressure signal is weighted "delta" > capacity unlike util_avg which is binary. > > It would also help, if you expanded on what you mean by binary in the > commit description and how the delta capacity is weighted. > > > + * capacity" here means delta between the actual capacity of a cpu and the > > + * decreased capacity a cpu due to a thermal event. > > This could be shortened to: > > Delta capacity of cpu = Actual capacity - Decreased capacity due to > thermal event >
Please ignore. I should have sent this against v9, it was languishing in my mailbox since v8 and I sent this out by mistake.
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